Injection device

ABSTRACT

An injection device for injecting a solid dose formulation into a human or animal body, the injection device comprising an actuator having a cassette mounting portion; a cassette holder having a cassette storage portion; and a cassette selectively movable between the cassette storage portion and the cassette mounting portion, wherein, the cassette comprises a solid dose formulation and the actuator is receivable in the cassette holder to selectively move the cassette between the cassette storage portion and the cassette mounting portion.

This application is a continuation of Ser. No. 15/548,250 filed Aug. 2,2017, which is the U.S. national phase of International Application No.PCT/GB2016/050226 filed Feb. 2, 2016, which designated the U.S. andclaims priority to GB Patent Application No. 1501697.5 filed Feb. 2,2015, the entire contents of each of which are hereby incorporated byreference.

An injection device particularly suited for, but not explicitly for,injecting a solid dose formulation into a human or animal body.

Solid dose formulations can be introduced into a human or animal body ateither low velocity through injection or high velocity fired from arifle. High velocity dosing is not appropriate for introducing a soliddose formulation into a human body hence substantial efforts have beenmade to develop a solid dose formulation having the requisite shape andmaterial properties to facilitate ease of injection into a human body.In some cases, solid dose formulations can be introduced into a humanbody by methods as simple as pushing the solid dose formulation throughthe skin without aid of a tool or device.

However, in order to avoid causing undue damage to the human body it isdesirable to introduce a solid dose formulation by applying only theforce necessary for the solid dose formulation to penetrate the humanbody. Human skin has a relatively low strength hence it is easy to applytoo great a force to the solid dose formulation using manual applicationmethods alone.

Use of a tool or device to introduce a solid dose formulation into ahuman body is known. Typically a tool, or a portion of such a tool,requires to be disposed of after a single use for hygiene and sanitationpurposes. The tool, or portion thereof, should be disposed of in such amanner that it is destroyed by means of incineration or otherwise. Thiscan be problematic as many medical tools or devices are constructed frommaterials with high temperature melting points. Medical tools anddevices are also expensive to manufacture and therefore disposal isundesirable.

The use of an actuator and cassette to inject a solid dose formulationinto a human body is known. Such an actuator and cassette is describedin PCT/EP2003/007859 which is hereby incorporated by reference.

It has been recognised that patients, in some circumstances, do not useinjection devices in the correct manner if left to follow instructionsprovided with the injection device. A demonstration on how to use aninjection device has been shown to reduce errors made by patients inusing injection devices. However, known injection devices typicallyrequire the patient to handle a cassette which contains a solid doseformulation. Any handling can compromise sterility of the cassette andthe solid dose formulation leading to potential infection at aninjection site.

The present invention seeks to address the aforementioned problems.

An aspect of the invention provides an injection device for injecting asolid dose formulation into a human or animal body, the injection devicecomprising an actuator having a cassette mounting portion; a cassetteholder having a cassette storage portion; and a cassette selectivelymovable between the cassette storage portion and the cassette mountingportion, wherein, the cassette comprises a solid dose formulation andthe actuator is receivable in the cassette holder to selectively movethe cassette between the cassette storage portion and the cassettemounting portion.

The injection device of the present invention eliminates the need for auser to handle the cassette thus maintaining sterility of the cassette.Preventing a user from handling the cassette also significantly reducesuser error in use of the injection device. The cassette of the presentinvention can be disposed of separately to the actuator and/or cassetteholder.

The cassette storage portion may comprise a plurality of releasableretaining elements for selectively retaining the cassette. The cassettemounting portion may comprise a bayonet fitting for receiving thecassette. The bayonet fitting of the cassette mounting portion and thereleasable fastening elements of the cassette storage portion may beco-operable such that rotation of the actuator in the cassette holderreleases the releasable fastening elements to facilitate selectivemovement of the cassette between the cassette storage portion and thecassette mounting portion.

The bayonet fitting of the cassette mounting portion may comprise alocking mechanism for locking the cassette to the bayonet fitting.

The locking mechanism is advantageous in that the cassette is preventedfrom being inadvertently detached from the actuator before actuation.

The cassette holder may comprise a cassette holder body and a cassetteholder insert, the cassette holder insert being removable from thecassette holder body and defining the cassette storage portion. Thecassette holder insert may be disposable.

The actuator may be re-usable.

A further aspect of the invention provides a method of injecting a soliddose formulation into a human or animal body, the method comprising: a)providing an injection device comprising an actuator, a cassette holderand a cassette, the cassette comprising a solid dose formulation b)selectively moving the cassette from the cassette holder to theactuator, c) operating the actuator to inject the solid dose formulationinto a human or animal body and d) selectively moving the cassette fromthe actuator to the cassette holder for disposal.

A further aspect of the invention provides a method of injecting a soliddose formulation into a human or animal body, the method comprising: a)providing an injection device comprising an actuator, a cassette holderand a cassette, the cassette comprising a solid dose formulation, b)aligning the actuator with the cassette holder, c) inserting theactuator into the cassette holder to engage the cassette, d) rotatingthe actuator relative to the cassette holder to lock the cassette to theactuator, e) withdrawing the actuator from the cassette holder, f)injecting the solid dose formulation into a human or animal body, g)aligning the actuator with the cassette holder, h) inserting theactuator into the cassette holder and i) rotating the actuator to lockthe cassette to the cassette holder.

Certain embodiments of the inventions are shown in the figures asdescribed below:

FIG. 1 shows illustrative views of an injection device according to thepresent invention comprising an actuator assembly and a cassette holder.

FIG. 2 shows a detailed view of the cassette holder of FIG. 1.

FIG. 3 shows a detailed view of a cassette holder insert which isinsertable into the cassette holder.

FIG. 4 shows a graph of the number of errors made per patient when usinga prior art injection device for the first time without receiving ademonstration prior to first use.

FIG. 5 shows a graph comparing the number of errors made per patientwhen using the device for the first time without a demonstration priorto first use and after receiving a demonstration prior to second use.

The certain embodiments will now be described by way of reference to thefigures.

Referring to FIG. 1, an actuator assembly 10 and cassette holder 20 areprovided for injecting a solid dose formulation into a human or animalbody.

The actuator assembly 10 comprises a body portion 12 and a cassettemounting portion 14. The body portion 12 houses a mechanism foroperating the actuator. The cassette mounting portion 14 is configuredto receive a cassette 34 comprising a solid dose formulation into abayonette type fitting 16, or similar.

As shown in FIG. 2, the cassette holder 20 comprises a cassette holderbody 22 which is open at one end. A cassette holder insert 24 isinsertable into the open end of the cassette holder body 22. The insert24 comprises a cassette storage portion 26 which stores the cassette 34.The cassette storage portion 26 is defined by three curved prongs 28which are biased to urge against the cassette 34 to hold it in position.The cassette holder body 22 and insert 24 are made from plastic in oneembodiment but the cassette holder 20 could also be made from metal. Inone embodiment the cassette holder body 20 and insert 24 are disposable.In other embodiments only the cassette holder insert 24 is disposable.

A plurality of cassette holders can be stored in a sterile packagingsuch as a vacuum formed packaging with individually removable seals.Alternatively, each individual cassette holder can have its own vacuumformed packaging, for example, and each packaged cassette holder can bestored in a non-sterile container

In use, the actuator assembly 10 is axially aligned with the cassetteholder 20. The cassette mounting portion 14 of the actuator assembly 10is inserted into the cassette holder 20. The dose cassette mountingportion is co-operable with the curved prongs 28 of the insert 24 suchthat rotation of the actuator assembly 10 through sixty degrees in apre-defined direction causes the actuator assembly 10 to act againstcurved prongs 28 and displace them relative to the cassette heldtherebetween. The cassette 34 is then released by the curved prongs 28and retained by the bayonet fitting 16. The actuator assembly 10 canonly be rotated through a maximum angle of approximately sixty degrees.Rotation is limited by a stop (not shown) defined on either the actuatorassembly 10 or within the cassette storage portion 26.

The cassette 34 comprises a dosing end (not shown) and a mounting end3). The mounting end 36 of the cassette 34 protrudes outwardly from thecassette holder insert 24. The mounting end 36 of the cassette 34comprises a bayonet type fitting, or similar, which is co-operable withthe bayonet type fitting 16 of the cassette mounting portion 14 of theactuator assembly 10. When the actuator assembly 10 is withdrawn fromthe cassette holder insert 24, the cassette 34 is retained by thebayonet fitting 16 of the actuator assembly 10.

The dosing end of the cassette 34 comprises the solid dose formulationand is exposed when the cassette 34 is retained by the actuator assembly10.

To inject the solid dose formulation into a human or animal body, thecassette 34 is held against the skin at ninety degrees therefrom. Theactuator assembly 10 is pushed downwards until an audible click can beheard. The click signifies that the actuator mechanism has operated andinjected the solid dose formulation from the cassette 34 through theskin and into the human or animal body. Once the solid dose formulationhas been injected, the actuator assembly 10 is withdrawn directly fromthe injection site.

After the solid dose formulation has been injected into a human oranimal body the actuator assembly 10 is axially aligned with thecassette holder 24. The Cassette mounting portion 14 of the actuatorassembly 10 is inserted into the cassette holder 20 after use. Rotationof the actuator assembly 10 through sixty degrees causes it to actagainst the three prongs 28 of the cassette holder insert 24. Theactuator assembly 10 can only be rotated through a maximum angle ofapproximately sixty degrees.

Rotation is limited by a stop (not shown) defined on either the actuatorassembly 10 or within the cassette storage portion 26. The three prongs28 are resiliently biased in a position in which they hold the cassette34 in place. The three prongs 28 are displaced by application of acompressive or torsional force to enable the cassette to enter or exit aspace defined between the prongs 28. Once the cassette 34 has enteredthe space between the prongs 28, the prongs 28 revert to theirunstressed configuration and retain the cassette 34. The dosing end ofthe cassette is orientated away from the open end of the cassette holderbody 22. The cassette holder 20 and/or cassette holder insert 24 is thendiscarded in a safe manner.

Injection devices were tested to evaluate handling of cassettes byusers. The following table sets out the sample data set used for theevaluation:

TABLE 1 Predominant Primary Insertion # Age Hand Known Dexterity IssuesSite 1 40 Right Received physio for Upper Thigh shoulder - 90% recovered2 40 Right None Abdomen 3 45 Left None Abdomen 4 51 Right None UpperThigh 5 42 Left None Upper Thigh 6 47 Right None Abdomen 7 60 Left NoneAbdomen 8 42 Left - ambi None Upper Thigh 9 63 Right None Upper Thigh 1059 Left Visible deformity to Abdomen hands - not diagnosed 11 53 RightSwollen index finger - Abdomen limited movement 12 55 Left Lockedwrist - limited grip, Upper Thigh left arm/hand weaker 13 65 Right NoneUpper Thigh 14 65 Right None Abdomen 15 57 Right None Abdomen 16 45Right None Upper Thigh 17 55 Right None Upper Thigh 18 64 RightArthritis in fingers Abdomen 19 54 Right Arthritis Abdomen 20 64 RightOp on elbow - affects grip Upper Thigh over long periods of time 21 64Right Osteo-athritis Upper Thigh 22 63 right Right wrist locks upAbdomen

For each patient, age, predominant hand, known dexterity issues andprimary injection site were recorded. Each patient was asked to use aninjection device following instructions provided with the device and thenumber of errors made by each patient in using the device were recorded(as summarised in FIG. 4).

The majority of errors occurred when the user handled the cassette. Eachuser was then given a demonstration on how to use the device and theerrors made were compared with the first use trial (as summarised inFIG. 5). The number of errors observed in the repeat use trial dropped77.5% in comparison to the first use trial. The evaluation thusindicated that there was a clear issue of patients using injectiondevices in an incorrect manner when left to follow the instructionsprovided with the injection device.

1. An injection device for injecting a solid dose formulation into ahuman or animal body, the injection device comprising: an actuatorhaving a cassette mounting portion; a cassette holder having a cassettestorage portion; and a cassette selectively movable between the cassettestorage portion of the cassette holder and the cassette mounting portionof the actuator, wherein, the cassette comprises a solid doseformulation and the actuator is receivable by the cassette holder toselectively move the cassette between the cassette storage portion andthe cassette mounting portion, and the cassette mounting portioncomprises a bayonet fitting for receiving the cassette and the bayonetfitting comprises a releasable locking mechanism for locking thecassette to the actuator.
 2. An injection device according to claim 1,wherein the cassette storage portion comprises a plurality of releasableretaining elements for selectively retaining the cassette.
 3. Aninjection device according to claim 2, wherein the bayonet fitting ofthe cassette mounting portion and the releasable retaining elements ofthe cassette storage portion are co-operable such that rotation of theactuator relative to the cassette holder releases the releasableretaining elements to facilitate selective movement of the cassette fromthe cassette storage portion to the cassette mounting portion and/orfrom the cassette mounting portion to the cassette storage portion. 4.An injection device according to claim 1 wherein the cassette holdercomprises a cassette holder body and a cassette holder insert, thecassette holder insert being removable from the cassette holder body anddefining the cassette storage portion.
 5. An injection device accordingto claim 1 wherein the actuator is a pressure activated actuator whichactuates the cassette to inject the solid dose formulation into a humanor animal body when an axial force is applied to the actuator in thedirection of the human or animal body.
 6. An injection device accordingto claim 6, wherein the cassette holder is made from plastic.
 7. Aninjection device according to claim 6, wherein the cassette holderinsert is disposable and the cassette holder body is re-usable.
 8. Aninjection device according to claim 1, wherein the actuator isre-usable.
 9. An injection device according to claim 4, wherein rotationof the actuator is limited by a stop defined by either the cassetteholder or the actuator.
 10. An injection device according to claim 4,wherein rotation of the actuator in the cassette holder is limited tosixty degrees in any direction.